RESUMEN

Reversible and remote cell manipulation with high spatiotemporal precision is now a highly attractive subject in various biological applications such as tissue engineering and cell-matrix interaction. Herein, photoresponsive poly(methyl methacrylate-co-hydroxy ethyl methacrylate-co-spiropyran ethyl acrylate) terpolymer (MHSP) was prepared using emulsion polymerization and the corresponding nanofibers (MHSP@NF) and film (MHSP@F) were prepared using electrospinning and drop-casting techniques, respectively. Structure of MHSP@NF with cylindrical cross-section and uniform diameter size of 169 nm were characterized by 1H-NMR and SEM analyses. Time-dependent UV-vis spectra of the prepared acrylic nanofibers and films demonstrated maximum forward photoisomerization after 3- and 8-min UV irradiation at 365 nm together with a 96° and 5° decrement in their surface water contact angles, respectively. High photoresponsivity of the nanofibers was attributed to their extensive surface area which exposes more spiropyran groups to UV light. MHSP@F and MHSP@NF with chemically-attached spiropyran groups demonstrated significant biocompatibility with negligible toxicity toward C6 glioma cancer cells up to 5 days. However, MH/SP@NF with doped SPOH exhibited a sudden decrease in cell viability relating to the migration and leakage of SPOH molecules. Photoreversible cell adhesion results showed a dramatic and switchable C6 cells attachment/detachment upon alternating UV and visible lights irradiations for MHSP@NF sample, while this was not observed for the similar film. These indicate potentiality of MHSP@NF as a promising substrate for dynamic switching of biomolecules and cell sheet engineering.

Asunto(s)

Glioma , Nanofibras , Benzopiranos , Humanos , Indoles , Nitrocompuestos

RESUMEN

In the present study, a polyaniline/carboxymethyl cellulose/TiO2 nanocomposite (PAn/CMC/TiO2) was synthesized by a polymerization method, and was used for adsorption of Congo Red from aqueous solution. The effects of operational parameters of the adsorption process including pH, initial dye concentration, temperature, adsorbent dosage, and adsorption time on adsorption efficiency were investigated, and response surface methodology was used for their optimization. Optimal adsorption conditions were determined at pH of 2.6, initial concentration of 82mgL, temperature of 56 °C, adsorption time of 24 min, and adsorbent dose of 0.14 g. In addition, the system was also simulated using artificial neural network (ANN) and genetic programming (GP). It was found that the behavior of the system could be well predicted by ANN using 5, 1 and 8 neurons for input, middle and output layers, respectively. Kinetic and isothermal analyses showed that the maximum adsorption capacities were obtained at 94.28, 97.53 and 119.9 mgg by Langmuir model at temperatures of 25, 40 and 50 °C, respectively and that adsorption kinetics followed the pseudo-second-order model. The nano-adsorbent was also found to be reusable without a significant change in adsorption capacity for at least five adsorption-desorption cycles. Finally, the mechanism of dye adsorption on the nano-adsorbent was investigated and proposed.